An employment tribunal is expected to hear claims today that one of Britain’s biggest police forces was a “boys' club” where sexual discrimination was rife.

The allegations against Northumbria Police, including sexual misconduct and misuse of public money by senior officers, have been made by Denise Aubrey, its former head of legal services.

Ms Aubrey, 54, was sacked for gross misconduct after being accused of passing on confidential details of sensitive matters involving senior officers to fellow solicitors employed by the force.

She denies the allegations and is suing the force, where she worked for more than 20 years until 2014, for wrongful dismissal, unfair dismissal following protected disclosures, victimisation, disability discrimination and sexual discrimination.

Unusually, the retired chief constable who was in charge at the time Ms Aubrey was dismissed is due to give evidence in her support.

Sue Sim left the force a month after she was cleared of misconduct over allegations of bullying made by a number of other senior officers. She later called for a police watchdog investigation into allegations of sexual discrimination in the force.

According to documents seen by The Times, the tribunal is expected to hear evidence that public money was spent on legal advice for a senior officer who was accused of having an extramarital affair.

Lawyers for several former senior officers are thought to be seeking a reporting ban on their identities being revealed during the hearing.

During her time with Northumbria Police, Ms Aubrey dealt with several high-profile cases including that of Raoul Moat, who shot dead the boyfriend of his former partner before shooting and blinding a police officer while on the run in 2010.